package com.ForkJoin;

import java.util.concurrent.RecursiveTask;

/**
 * @author WXJ
 * @descrption
 * @create 2020/4/16 16:51
 **/
public class ForkJoinCalculate extends RecursiveTask<Long> {

    private long start;
    private long end;

    private static final long THRESHOLD = 10000;

    public  ForkJoinCalculate(long start,long end){
        this.start = start;
        this.end = end;

    }

    @Override
    protected Long compute() {
        long length= end - start;

        if (length<= THRESHOLD){
            long sum = 0;
            for (long i = start;i<=end ;i++){
                sum += i;
            }
            return sum;
        }else {
            long middle = (start + end) / 2;
            ForkJoinCalculate left = new ForkJoinCalculate(start,middle);
            left.fork();//拆分子任务，同时压入线程队列

            ForkJoinCalculate right = new ForkJoinCalculate(middle+1,end);
            right.fork();
            return left.join() + right.join();  //合并任务
        }

//        return null;
    }
}
